1. Field of Invention
This invention relates to introducers. More particularly, this invention relates to guiding introducers of specific shapes for use within the left ventricle of the human heart for the treatment of left ventricular tachycardia.
2. Prior Art
Introducers and catheters have been in use for medical procedures for many years. For example, one use has been to convey an electrical stimulus to a selected location within the human body. Another use is to monitor and make measurements for diagnostic tests within the human body. Catheters may be used by a physician to examine, diagnose and treat while positioned at a specific location within the body which is otherwise inaccessible without more invasive procedures. In use, catheters may be inserted into a major vein or artery which is near the body surface. These catheters are then guided to the specific location for examination, diagnosis or treatment by manipulating the catheter through the artery or vein of the human body.
Catheters have become increasingly useful in remote and difficult to reach locations within the body. However, the utilization of these catheters is frequently limited because of the need for the precise placement of the tip of the catheter at a specific location within the body.
Control of the movement of catheters to achieve such precise placement is difficult because of the inherent structure of a catheter. The body of a conventional catheter is long and tubular. To provide sufficient control of the movement of the catheter, it is necessary that its structure be somewhat rigid. However, the catheter must not be so rigid as to prevent the bending or curving necessary for movement through the vein, artery or other body part to arrive at the specified location. Further, the catheter must not be so rigid as to cause damage to the artery or vein while it is being moved within the body.
While it is important that the catheter not be so rigid as to cause injury, it is also important that there be sufficient rigidity in the catheter to accommodate torque control, i.e., the ability to transmit a twisting force along the length of the catheter. Sufficient torque control enables controlled maneuverability of the catheter by the application of a twisting force at the proximal end of the catheter that is transmitted along the catheter to its distal end. The need for greater torque control often conflicts with the need for reduced rigidity to prevent injury to the body vessel.
Catheters are used increasingly for medical procedures involving the human heart. In these procedures a catheter is typically advanced to the heart through veins or arteries and then is positioned at a specified location within the heart. Typically, the catheter is inserted in an artery or vein in the leg, neck, upper chest or arm of the patient and threaded, often with the aid of a guidewire or introducer, through various arteries or veins until the tip of the catheter reaches the desired location in the heart.
The distal end of a catheter used in such a procedure is sometimes preformed into a desired curvature so that by torquing the catheter about its longitudinal axis, the catheter can be manipulated to the desired location within the heart or in the arteries or veins associated with the heart. For example, U.S. Pat. No. 4,882,777 discloses a catheter with a complex curvature at its distal end for use in a specific procedure in the right ventricle of a human heart. U.S. Pat. No. 5,231,994 discloses a guide catheter for guiding a balloon catheter for the dilation of coronary arteries. U.S. Pat. No. 4,117,836 discloses a catheter for the selective coronary angiography of the left coronary artery and U.S. Pat. Nos. 5,215,540, 5,016,640 and 4,883,058 disclose catheters for selective coronary angiography of the right coronary artery. U.S. Pat. No. 5,242,441 discloses a deflectable catheter for ablation procedures in the ventricular chamber. See also U.S. Pat. No. 4,033,331. In addition, U.S. Pat. No. 4,898,591 discloses a catheter with inner and outer layers containing braided portions. The '591 patent also discloses a number of different curvatures for intravascular catheters. Thus, there are a number of references which disclose catheters with predetermined shapes, designed for use during specific medical procedures generally associated with the heart or the vascular system. Because of precise physiology of the heart and the vascular system, catheters or introducers with precisely designed shapes for predetermined uses within the human heart and vascular system are increasingly important.
Catheter ablation of accessory pathways using a long vascular sheath by means of a transseptal or retrograde approach is discussed in Saul, J. P., et al. "Catheter Ablation of Accessory Atrioventricular Pathways in Young Patients: Use of long vascular sheaths, the transseptal approach and a retrograde left posterior parallel approach" J. Amer. Coll. Card., Vol. 21, no. 3, pps 571-583 (Mar. 1, 1993). See also Swartz, J. F. "Radiofrequency Endocardial Catheter Ablation of Accessory Atrioventricular Pathway Atrial Insertion Sites" Circulation, Vol. 87, no. 2, pps. 487-499 (February, 1993).
U.S. Pat. No. 4,641,649 discloses the use of high frequency energy for the treatment of tachycardia or cardiac dysrhythmia. See also U.S. Pat. Nos. 5,246,438 and 4,945,912 for the use of radio frequency energy for ablation of cardiac tissue. In addition, various articles have disclosed the ablation of specific locations within the heart by use of energy, in particular, radio frequency energy. See, for example, Gallagher, J. J. et al. "Catheter Technique for Closed-Chest Ablation of the Atrioventricular Conduction System" N. Engl. J. Med. Vol. 306, pp. 194-200 (1982); Horowitz, L. N. "Current Management of Arrhythmia" pp. 373-378 (1991); Falk, R. H. et al. "Atrial Fibrillation Mechanics and Management" pp. 359-374 (1992); and Singer, I. "Clinical Manual of Electrophysiology" pp. 421-431 (1993).
In addition, U.S. Pat. No. 5,172,699 discloses a general process for the identification and ablation of ventricular tachycardia sites. See also U.S. Pat. Nos. 5,222,501 and 5,242,441.
In addition, the use of radio frequency ablation energy for the treatment of Wolff-Parkinson-White Syndrome in the left atrium by use of a transseptal sheath is disclosed in Swartz, J. F. et al. "Radiofrequency Endocardial Catheter Ablation of Accessory Atrioventricular Pathway Atrial Insertion Sites" Circulation 87:487-499 (1993). See also Tracey, C. N. "Radio Frequency Catheter Ablation of Ectopic Atrial Tachycardia Using Paced Activation Sequence Mapping" J. Am. Coll. Cardiol. 21:910-917 (1993).
Accordingly, it is an object of this invention to prepare a guiding introducer for selected medical procedures in the left ventricle.
It is a further object of this invention to prepare a guiding introducer for use in selected electrophysiology procedures within the left ventricle of the heart.
Another object of this invention is to prepare a guiding introducer for use in selected ablation procedures within the left ventricle of the heart.
It is a still further object of this invention to prepare a guiding introducer for use in the selected ablation of sites in the left ventricle of the heart for the treatment of left ventricular tachycardia.
These and other objects are obtained by the design of the guiding introducers disclosed in the instant invention.